Marian, Daniela. “Some Types of Convex Functions on Networks”. Rev. Anal. Numér. Théor. Approx. 38, no. 1 (February 1, 2009): 51–63. Accessed May 17, 2024. https://ictp.acad.ro/jnaat/journal/article/view/2009-vol38-no1-art5.